Golf club head or face

ABSTRACT

A striking face for golf clubs, such as a driver, iron or putter, includes zones of the same or different material arranged to create a desired “feel” to the golfer and/or produce a desired effect on the golf ball. For instance, the zones can be arranged to create a variation in mechanical properties across the striking face. The zones can be created by using “pixels” such as round or hexagonal rods arranged with their central axes perpendicular to the striking face. Pixels of a first material such as a shape memory alloy such as superelastic NiTi can be arranged in one or more concentric patterns and the remainder of the striking face can be made up of pixels of a second material such as beta-titanium, martensitic NiTi or stainless steel. The superelastic NiTi pixels can thus create a sweet spot on the striking face of the club.

FIELD OF THE INVENTION

[0001] The invention relates to improvements in construction of golfclub heads and faces for golf clubs such as a driver, iron or putter.

BACKGROUND OF THE INVENTION

[0002] A large variety of materials have been proposed and in fact usedand offered commercially as golf club heads and faces. These materialshave been applied monolithically or as inserts in the club face in anattempt to achieve more distance and/or more control over the ball. Thelist of materials includes polymers, ceramics, and metals, typically themost common, stainless steels, BeCu, and lately various titanium alloys,and shape memory materials such as NiTi based and copper based alloys.

[0003] Each of these materials has individual properties, different fromeach other but basically uniform unto themselves and hence provide asurface on a golf club that impacts the golf ball with essentiallyuniform mechanical properties across the face. For example, a typicaltitanium alloy such as Titanium 6-4 has a modulus of about 15 millionpsi and a yield strength of about 120,000 psi at a stain of less than1%. Other materials will have different moduli and different yieldstrengths with different associated strain levels but as noted uniformproperties as to themselves as used on the face of a golf club.

[0004] Since the mechanical characteristics (club speed, materialsproperties, geometry) at the impact of the club face with the balldetermine the course (trajectory, distance, dispersion) of the ball;control of the materials properties can be key to control of the courseof the ball. Club head speed and geometry being constant or independentof the specific properties of the material used as the impact surface ofthe club.

SUMMARY OF THE INVENTION

[0005] The invention provides a golf ball striking face of a golf clubwherein first and second zones of material are distributed across thestriking face, one or more of the first zones being surrounded by one ormore of the second zones and the one or more first zones having a higheror lower modulus of elasticity than the one or more second zones. Thefirst and second zones can be differentially heat treated zones of aunitary piece of metallic material. Alternatively, a plurality of thefirst zones can comprise discrete pieces of a first material such as ashape memory alloy and the second zone can comprise a unitary piece of asecond material such as β-titanium or stainless steel wherein the firstzones are embedded in the second material.

[0006] According to various embodiments of the invention, a plurality ofthe first zones can comprise individual wire segments arranged in apattern with central axes of the wire segments intersecting an exposedsurface of the striking face. The striking face can be planar ornon-planar. A plurality of the first zones can comprise discrete piecesarranged in a pattern and the second zone can comprise a framesurrounding the first zones. The first zones can have various shapessuch as polyhedral shapes, cylindrical shapes or any other desiredshape. A plurality of the second zones can be separated by a pluralityof the first zones such as alternating rings of first and second zones.For example, the first zones can comprise an annular ring and the secondzones can include an inner second zone surrounded by the first zone andan outer second zone surrounding the first zone. The first zones cancomprise a perimeter weighting arrangement of an insert or club head ofa golf club. Alternatively, third zones of material can surround thefirst and second zones wherein the third zones comprise a dense materialproviding perimeter weighting of an insert or club head of a golf club.The first zones can comprise solid or hollow metallic members. Forexample, the one or more first zones can comprise wires of singlecrystal CuNiAl and the wires can be arranged with central axes thereofintersecting the striking face.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007]FIG. 1 shows a golf club incorporating a striking face inaccordance with the invention;

[0008]FIG. 2 shows a “pixel” arrangement in accordance with theinvention;

[0009]FIGS. 3-13 show various “pixel” arrangements in accordance withthe invention;

[0010]FIG. 14 shows a “pixel” arrangement in accordance with theinvention wherein the striking face is non-planar;

[0011]FIG. 15 shows a “pixel” arrangement in accordance with theinvention wherein the wires forming the individual pixels comprisecurved wire segments;

[0012]FIG. 16 shows a “pixel” arrangement in accordance with theinvention wherein the pixels comprise tubes;

[0013]FIGS. 17-21 show an embodiment of the invention wherein a plate ofmaterial is differentially heat treated to create zones having differentproperties;

[0014]FIGS. 22-23 show an embodiment of the invention wherein the firstzones comprise inserts received in grooves of a base material;

[0015]FIG. 24 shows a stress/strain curve of a wire sample of a singlecrystal CuNiAl wire;

[0016]FIGS. 25-26 show an embodiment of the invention incorporatingperimeter weighting; and

[0017]FIG. 27 shows a prior art perimeter weighting arrangement.

DETAILED DESCRIPTION OF THE INVENTION

[0018] The invention allows the mechanical properties of the strikingface of a golf club to be controlled and varied at will in incrementalareas on the impact face of the club of as small as 0.0001 squareinches. Use of the invention can hence allow the properties of the clubface to vary in any pattern over the impact area. As shown in FIG. 1, anelliptically-shaped “sweet spot” 2 on the club face 4 of a driver-typegolf club 6 can be created that varies mechanical properties inconcentric rings (or any other desirable patterns) in the impact areafrom high modulus to low modulus and/or any combination of high yieldstrength and elastic stain characteristics. An analogy to aid inunderstanding the invention, is a TV screen. Picture the TV screen asthe impact area of the golf club and the individual pixels asindividually selectable materials from the whole gamut of availablematerials. One can then see that any conceivable pattern or combinationof materials properties can be achieved on the “screen” (impact face) bysimply selecting the pixels, as desired, by analogy as a TV image on thescreen can be generated. Further picture the individual pixelsthemselves as having selectable geometry such as round or hexagonalshape. For example, if hexagonal geometry were chosen for individualpixels, the pixels would stack in a manner essentially “tight packed”allowing almost no space between individual pixels while if a roundgeometry is chosen, the stacked pixels 8 would create interstices 10(see FIG. 2) between pixels that in turn could be made from anydesirable material either the same or different from the round pixelsthemselves. It can be seen that an infinite combination of materialsproperties can be created by the combination of choice of “pixel” sizeand shape and material. The range of the invention allows, at one enduniform properties across the golf club face by selection of a singlematerial, and at the other end an infinite variation of properties inany pattern across the face, by selection of the “pixel” size, shape andmaterial.

[0019] The method to create the striking face according to the inventionis quite simple. Using the TV screen analogy, picture the pixels as theends of individual wires of selected materials such as titanium orpolymer or preferably highly elastic shape memory materials (e.g., NiTibased materials). As shown in FIG. 3, the hexagonal-shaped wires 12 aretightly packed into a frame 14 and bonded in a matrix of epoxy polymer(or sintered metal powder or solder or other adhesive matrix). Thisframe is made to the proper size for an insert 16 on the face of a golfclub, either a driver or an “iron” or putter. The framed matrix of“pixels” of wire is then formed by machining or grinding to club facegeometry and applied to a club. The resulting insert 16 as noted abovecan be designed to any desirable combination of materials propertiessimply by selecting the desired wire materials and diameters or crosssectional geometry. FIGS. 4-7 illustrate the invention in several forms.FIG. 4 shows round “pixels” 18 of uniform diameter in a matrix 20 ofepoxy polymer. FIG. 5 shows the pixels 22 as tight packed hexagon crosssections, FIG. 6 shows a frame 24 which mates with the hexagon-shapedpixels, and FIG. 7 shows a combination including a variation of pixelsizes 26,28. Note that the frame can be retained as part of the insertor removed after the “pixels” are bonded together.

[0020] As noted above the pixels may also vary in material selection.FIG. 1 illustrates an elliptical “sweet spot” 2 in which the centralzone is of a material with a high modulus and progressively the modulusis varied toward the borders of the impact face by selecting materialswith progressively lower modulus. Of course, the opposite combination ofmaterials properties (e.g., low modulus at the center/high modulus atthe outside) could be implemented or any other combination or a uniformmaterial could be selected.

[0021] The preferred embodiments of the invention include versionsdesigned for maximum control (minimum dispersion), maximum distance, orideal combinations of distance and control. Various patterns for theimpact zone are illustrated in FIGS. 8-16 wherein pixels 30, 32, 34, 36,38, 40, 42, 44, 46, 48, 50 are arranged within frames 52, 54, 56, 58,60, 62, 64.

[0022] The thickness of the “pixel” matrix can also be varied to createa “z” axis variation in mechanical response of the club face. Thisthickness variation can be accomplished by machining of the front orback or both sides of the framed insert or the impact surface of theinsert can consist of shorter and longer “pixels” that create a 3dimensional effect on the impact surface as illustrated in FIG. 14wherein striking face 66 has a curvature of radius R and the pixels 46increase in length towards the middle of frame 60. Since materials canbe individually selected for properties, surface geometry of the impactsurface can also be modified and customized by selective chemicaletching of the surface. For example, if a combination of titanium-nickeland aluminum “pixels” were selected, chemical etching of the impactsurface using a strong basic solution would result in the aluminumelements being etched away at a rate much higher than thenickel-titanium materials. The surface therefore would exhibit raisednickel-titanium elements among lowered aluminum elements. This samebasic process can be applied to a variety of materials includingpolymers to achieve a surface on the impact zone to idealize grip orspin imparted to the ball similar to the now conventional grooves, dots,holes and indents found on club faces. This process can also be used toproduce differences in coloration of the materials, which by controllingpatterns of application can be used to produce visually observablelogos, designs and/or service marks such as company names on the surfaceto the inserts.

[0023] The frame constraining the pixel matrix can be made of materialssuch as stainless steel, by machining, forging or casting. A polymerframe may also be created by molding or machining. A temporary frame maybe used to create the insert form as a matrix bonded together by epoxyresin and then the fame may be removed leaving a frameless insert forapplication to the club face in an appropriate recess or receivingcavity on the club. The back side of the “pixel” matrix may be supportedby the frame structure or the receiving cavity of the club may supportthe backside of the matrix or both in combination.

[0024] In another variation of the invention, the individual wires 48(“pixels”), may be curved or bowed (see FIG. 15) to allow bothcompression and bending strain upon impact with the ball. The individualpixels 50 may also be hollow; for example, thin wall tubes either emptyor the lumen filled with another material such as polymer or alternatelyfilled or partially filled with metal or polymer or ceramic material, asshown in FIG. 16.

[0025] The invention is additionally illustrated in connection with thefollowing Examples which are to be considered as illustrative of thepresent invention. It should be understood, however, that the inventionis not limited to the specific details of the Examples.

[0026] “Driver” Example:

[0027] An insert for a golf club “driver” consisting of optimizedelastic nickel-titanium wires and beta titanium wires in an epoxy matrixwith the higher modulus beta titanium wires forming an outer circularzone of impact and the lower modulus nickel-titanium forming a circularinner zone of impact. This embodiment allows a combination of longdistance from the high modulus beta titanium and control from the lowermodulus very highly elastic non linear strain characteristics of thenickel-titanium. This arrangement approximates the strain distributionon the ball as it is deformed by the face of the club. Closerapproximations are possible by reducing the size of the pixels andadding a third or fourth material and so on with moduli progressivelyvarying. The “opposite” example could consist of high modulus betatitanium or even higher modulus stainless steel forming an inner zonewith NiTi lower modulus forming an outer zone.

[0028] “Iron” Example:

[0029] An insert for a golf club “iron” consisting of a matrix ofhexagonal wires per the invention made from highly damping superelasticNiTi alloy or a combination of superelastic NiTi and martensitic NiTialloy materials. This embodiment would allow a solid yet vibrationreduced feel upon impact since the NiTi material in a superelastic oroptimized elastic condition has a damping effect resulting from energyabsorption deriving from its stress/strain hysterises behavior.

[0030] “Putter” Example:

[0031] An insert for a golf club putter consisting of a matrix ofmartensitic NiTi wires alone or in combination with polymer wires. Thisembodiment is designed to maximize damping (vibration reduction) onimpact with a resulting “dead” or “soft hit” feel for maximum control ofthe ball in putting.

[0032] “Differentially Heated Treated”Example

[0033]FIG. 17 shows an insert 70 for a golf ball striking surface of agolf club wherein the insert is a solid piece of NiTi based shape memoryalloy. The solid piece of NiTi is differentially heat treated such as ina uniform or non-uniform pattern to control the mechanical propertiesacross the interface and achieve an effect similar to the “pixel”approach discussed above. The differential heat treatment preferablyprovides finite zones 72 surrounded by or surrounding adjacent zoneswhich are unaffected by the heat treatment. The heat treatment can beimplemented, for example, by patterning electrodes arrangedperpendicular to and opposing the surface being heat treated and passingAC or DC current through the electrodes. The heat treatment step can becarried out by running electrical current from electrode to electrodethrough the material in order to effect localized heating and provideone or more heat treated zones corresponding to the shape or shapes ofthe opposed electrodes. In FIG. 17, a nickel-titanium based shape memoryalloy insert 70 for a club face is located between a pair of opposedelectrodes 74,76. FIG. 18 shows a plan view of the NiTi insert 70differentially heat treated in FIG. 17. As shown in FIG. 18, the heattreated zone 72 is circular in shape. In heat treating the insert, asingle pair of electrodes could be used to sequentially provide a seriesof heat treated zones 72 or a plurality of electrodes provided in adesired pattern and having a desired configuration could be used tocreate any desired pattern of heat treated zones.

[0034]FIGS. 19-21 show examples of patterns of heat treated zones 78,80, 82 which can be obtained by differentially heat treating NiTi 84,86, 88 inserts for golf club faces. As shown in these figures, bypatterning the electrodes and/or by the geometry of the electrodesthemselves, differential mechanical properties can be achieved in largevariety of patterns that can be idealized for control of the flight of agolf ball. FIG. 19 shows a heat treated zone 78 in the shape of anannular ring and such a heat treated zone could be created by a pair ofopposed tubular electrodes. FIG. 20 shows a ring of circular heattreated zones which together form an annular zone 80 created by one ormore pairs of opposed electrodes of the type shown in FIG. 17. FIG. 21shows an example of “strip” heat treated zones 82 created by one or morepairs of opposed strip electrodes (e.g., plate-type electrodes).

[0035] “Composite” Example

[0036]FIGS. 22-23 show an example of a composite insert 90 for astriking face of a golf club. As shown in FIG. 22, the insert includes abase material 92 having one or more embedded members 94 of a materialselected for purposes of modifying the properties of the insert. Forinstance, as shown in FIG. 22, the additional members 94 can be spacedmore closely together in the central region of the insert than at theouter edges thereof. As shown in FIG. 23, the base material can includegrooves 96 for receiving the additional members 94. The grooves can beprovided in any desired pattern such as a uniform pattern or nonuniformpattern (e.g., the grooves can be provided with progressively increasingspacing therebetween towards the outer periphery of the insert). Thematerial of the inserts preferably provides a different modulus than thebase material. Although the grooves are shown as extending verticallythe grooves could extend in any desired direction or have any desiredshape (e.g., the grooves could be provided in a horizontal, angled ormixed pattern which combines more than one shape or orientation of thegrooves).

[0037] “CuNiAl Single Crystal” Example

[0038] An insert for a string face of a golf club includes “pixels” (asdescribed earlier) of single crystal CuNiAl. Such an insert would allowmuch greater deformations of the club insert striking surface. Thismaterial has extreme strain ability to deform elastically up to 12-14%strain with a “plateau” at low stress and full elastic recovery withvery low hysteresis. FIG. 24 is a stress/strain curve of a wire sampleof single crystal CuNiAl having a diameter of 0.060 inch. The strainproperties of such material would allow a golf ball to remain on theclub for a longer period of time giving an increased feel of control tothe user.

[0039] “Perimeter Weighting” Example

[0040]FIG. 25 shows an example of how perimeter weighting can be addedto the golf club according to the invention. In the embodiment shown,the central region 100 of the club face can include a pixel or otherarrangement such as shown in FIGS. 1-23. The central region is entirelyor partly surrounded by high density “pixels” 102 such as rods of heavymaterials such as pure metals (e.g., uranium, tungsten, molybdenum,lead, etc.). The perimeter weighting concept allows the striking face tobe made much thinner. For instance, as shown in FIG. 26, thecross-section of an “iron-type” club face 104 having the perimeterweighting 102 can be substantially uniform in thickness whereas aconventional cast or forged stainless steel iron-type club, such as isshown in FIG. 27, has an increased cross-section around the top 106 andbottom 108 thereof.

[0041] The foregoing has described the principles, preferred embodimentsand modes of operation of the present invention. However, the inventionshould not be construed as being limited to the particular embodimentsdiscussed. Thus, the above-described embodiments should be regarded asillustrative rather than restrictive, and it should be appreciated thatvariations may be made in those embodiments by workers skilled in theart without departing from the scope of the present invention as definedby the following claims.

What is claimed is:
 1. A golf ball striking face of a golf club,comprising: first and second zones of material distributed across thestriking face, one or more of the first zones being surrounded by one ormore of the second zones and the first zone having a higher or lowermodulus of elasticity than the second zone.
 2. The golf ball strikingface of claim 1, wherein the first and second zones are differentiallyheat treated zones of a unitary piece of metallic material.
 3. The golfball striking face of claim 1, wherein a plurality of the first zonescomprise discrete pieces of a first material and the second zonecomprises a unitary piece of a second material, the first zones beingembedded in the second material.
 4. The golf ball striking face of claim1, wherein a plurality of the first zones comprise discrete pieces of asuperelastic shape memory alloy.
 5. The golf ball striking face of claim1, wherein a plurality of the first zones comprise individual wiresegments arranged in a pattern, the wire segments being arranged withcentral axes thereof perpendicular to an exposed surface of the strikingface.
 6. The golf ball striking face of claim 1, wherein a plurality ofthe first zones comprise discrete pieces arranged in a pattern and thesecond zone comprises a frame surrounding the first zones.
 7. The golfball striking face of claim 6, wherein the first zones have polyhedralshapes.
 8. The golf ball striking face of claim 1, wherein a pluralityof the second zones are separated by a plurality of the first zones. 9.The golf ball striking face of claim 1, wherein the striking face isplanar or non-planar.
 10. The golf ball striking face of claim 1,wherein the striking face comprises an insert for an iron-type golf cluband the insert has a substantially uniform thickness.
 11. The golf ballstriking face of claim 1, wherein the first zone comprises an annularring and a plurality of the second zones include an inner second zonesurrounded by the first zone and an outer second zone surrounding thefirst zone.
 12. The golf ball striking face of claim 1, wherein the oneor more first zones comprise a perimeter weighting arrangement of aninsert or club head of a golf club.
 13. The golf ball striking face ofclaim 1, further comprising third zones of material surrounding thefirst and second zones, the third zones comprising a dense materialproviding perimeter weighting of an insert or club head of a golf club.14. The golf ball striking face of claim 1, wherein the first zonescomprise a plurality of solid or hollow metallic members.
 15. The golfball striking face of claim 1, wherein the first zones comprise wires ofsingle crystal CuNiAl, the wires being arranged with central axesthereof intersecting the striking face.
 16. The golf ball striking faceof claim 1, wherein the first zones comprise wire segments, the wiresegments being curved and arranged with ends of the wire segmentsintersecting the striking face.